[ARM] Adjust strcmp-armv7.S selection logic.

[Marcus Shawcroft <marcus dot shawcroft at arm dot com>]

Reformulate the strcmp-armv7.S selection logic around the architecture
features required by the implementation code rather (some) version of
the architecture that expose those features.


OK ?

/Marcus

      * libc/machine/arm/strlen-stub.c: Adjust strlen-armv7.S selection 
logic.
        * libc/machine/arm/strlen.S: Likewise.

diff --git a/newlib/libc/machine/arm/strlen-armv7.S b/newlib/libc/machine/arm/strlen-armv7.S
index 4ce0182..9dce6f2 100644
--- a/newlib/libc/machine/arm/strlen-armv7.S
+++ b/newlib/libc/machine/arm/strlen-armv7.S
@@ -29,9 +29,35 @@
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    Assumes:
-   ARMv6T2, AArch32
+   ARMv6T2 or ARMv7E-M, AArch32
  */
 
+/* Copyright (c) 2015 ARM Ltd.
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+       * Redistributions of source code must retain the above copyright
+	 notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+	 notice, this list of conditions and the following disclaimer in the
+	 documentation and/or other materials provided with the distribution.
+       * Neither the name of the Linaro nor the
+	 names of its contributors may be used to endorse or promote products
+	 derived from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  */
+
 #include "arm_asm.h"
 
 	.macro def_fn f p2align=0
@@ -51,6 +77,12 @@
 #endif
 
 	/* This code requires Thumb.  */
+#if __ARM_ARCH_PROFILE == 'M'
+	.arch   armv7e-m
+#else
+	.arch	armv6t2
+#endif
+	.eabi_attribute Tag_ARM_ISA_use, 0
 	.thumb
 	.syntax unified
 
diff --git a/newlib/libc/machine/arm/strlen-stub.c b/newlib/libc/machine/arm/strlen-stub.c
index 97500e0..bcd3d2d 100644
--- a/newlib/libc/machine/arm/strlen-stub.c
+++ b/newlib/libc/machine/arm/strlen-stub.c
@@ -44,7 +44,7 @@
 #if defined __thumb__ && ! defined __thumb2__
 #include "../../string/strlen.c"
 
-#elif (__ARM_ARCH >= 7 && defined __ARM_ARCH_ISA_ARM) || defined __ARM_ARCH_6T2__
+#elif __ARM_ARCH_ISA_THUMB >= 2 && defined __ARM_FEATURE_DSP
   /* Implemented in strlen.S.  */
 
 #else
diff --git a/newlib/libc/machine/arm/strlen.S b/newlib/libc/machine/arm/strlen.S
index e0dd122..5737145 100644
--- a/newlib/libc/machine/arm/strlen.S
+++ b/newlib/libc/machine/arm/strlen.S
@@ -39,7 +39,7 @@
 #if defined __thumb__ && ! defined __thumb2__
   /* Implemented in strlen-stub.c.  */
 
-#elif (__ARM_ARCH >= 7 && defined __ARM_ARCH_ISA_ARM) || defined __ARM_ARCH_6T2__
+#elif __ARM_ARCH_ISA_THUMB >= 2 && defined __ARM_FEATURE_DSP
 #include "strlen-armv7.S"
 
 #else
-- 
1.9.1